fix(ai-export): strip photo metadata and minimize the training payload

lib/features/session/session_provider.dart

@@ -6,6 +6,7 @@ class SessionProvider extends ChangeNotifier {
   DateTime? get sessionDate => _sessionDate;
   String? _currentWeaponName;
   String? _currentWeaponId;
+  String? _currentWeaponCaliber;
   int _shotsPerTarget = 5;
   int _distance = 25;
   String? _activeSessionId;
@@ -14,6 +15,11 @@ class SessionProvider extends ChangeNotifier {
 
   String? get currentWeapon => _currentWeaponName;
   String? get currentWeaponId => _currentWeaponId;
+
+  /// Calibre de l'arme de la session. Contrairement au nom d'arme, il ne
+  /// designe pas l'utilisateur : c'est la seule donnee d'arme envoyee au
+  /// backend d'entrainement (le diametre des trous en depend).
+  String? get currentWeaponCaliber => _currentWeaponCaliber;
   int get shotsPerTarget => _shotsPerTarget;
   int get distance => _distance;
   bool get isSessionActive => _isSessionActive;
@@ -23,9 +29,10 @@ class SessionProvider extends ChangeNotifier {
   int get totalSessionScore => _currentAnalyses.fold(0, (sum, a) => sum + a.totalScore);
   int get targetCount => _currentAnalyses.length;
 
-  void startSession(String weaponName, int shots, String sessionId, {String? weaponId, int distance = 25, DateTime? date}) {
+  void startSession(String weaponName, int shots, String sessionId, {String? weaponId, String? caliber, int distance = 25, DateTime? date}) {
     _currentWeaponName = weaponName;
     _currentWeaponId = weaponId;
+    _currentWeaponCaliber = caliber;
     _shotsPerTarget = shots;
     _distance = distance;
     _sessionDate = date ?? DateTime.now();
@@ -45,6 +52,7 @@ class SessionProvider extends ChangeNotifier {
     _activeSessionId = null;
     _currentWeaponId = null;
     _currentWeaponName = null;
+    _currentWeaponCaliber = null;
     _currentAnalyses.clear();
     _distance = 25;
     notifyListeners();